The invention relates to a device for drilling through a stratum as generically defined by the preamble to claim 1.
The device is usable in the gas and oil industry for forming a hydrodynamic connection (channels) between a fluid-saturated stratum and a borehole (perforation).
A device for drilling through a formation is known (Patent No. 2070358 E 21 B 43/11), which has a body with a longitudinally oriented cutout in a wall. Also provided are: a suspension in the form of pipes for a body; a cutting rod, which is accommodated opposite the longitudinally oriented cutout of the body, a control bushing and bushing, and is set up rotatably in a ball-and-socket joint; a pivot point in the form of a hydraulic motor; a rotation transmission point in the form of a link mechanism; an in-feed point of a cutting rod, which represents a ball-and-socket joint that is braced on the bushing and which cooperates with a cushioned control bushing; and a hydraulic anchor cut.
One problem of this known device is the lack of cutting value feedback (of the torque and the contact pressure of the cutting rod), which leads to overloads on the lower joint of the rotation transmission point. The cutting edges of the cutting rod are colored, and a serial-rail hydraulic motor is used, which is predetermined for work with axial pressure compensation upon loading onto a chisel. When cutting, the device points toward the opposite wall and thus reduces drilling depth.
The device which drills through a formation (Patent No. 92145563 E 21 B 43/11) and is selected as a prototype for the invention has a body with a longitudinally oriented cutout in the wall; a body suspension in the form of pipes; a cutting rod placed opposite the longitudinally oriented cutout in the body on a control bushing and bushing, and disposed rotatably in a ball-and-socket joint; a pivot point embodied in the form of a hydraulic motor for a mine level; a cutting rod in-feed point, which has a ball-and-socket joint in the form of a ball truncated on a side, that is braced on the bushing and represents a cushioned control bushing cooperating with the bushing; an anchor cut, which is embodied in the form of a hydraulically imbalanced bush with wedges mounted in articulated fashion thereon; a rotation transmission point in the form of a link mechanism, which is distinguished in that the device is additionally equipped with a feedback point in the form of a constricting element that is disposed in the annular gap between the control bushing and the pivot point shaft; a pressure point of the device toward the borehole wall, in the form of one or more rotary bodies, which is or are disposed in the body and in the control bushing opposite the longitudinally extending cutout in the body; and an axial bearing and infeed point of the cutting rod introduced into the spindle construction of the pivot point, with the possibility of absorbing operating pressure from the feedback point.
Above-ground testing patterned after the model device for drilling, as embodied in Patent N92145663, revealed that at the conclusion of the cutting cycle, the device failed to return to the position required for transport (the axis of the cutting rod coincides with the axis of the device). In-feeding of the cutting element is done at the expense of rotating the ball-and-socket joint (braced on the bushing) about the horizontal axis of rotation when the control elements interact. The control elements are placed eccentrically relative to the horizontal axis of rotation and are formed by cylindrical pins secured to the ball-and-socket joint, which are guided in horizontal cutouts in the control bushing as they are displaced downward. To strengthen the control element/detail pairing, a sliding placement of the ball-and-socket joint in the control bushing is employed with some tension. Therefore, upon the control bushing's return motion, the ball-and-socket joint is simply lifted away via the bushing and remains in the operating position. The kinematic connection of the ball-and-socket joint to the body (resulting from the cutting operation when the joint interacts with the bushing secured in the body), is wasted during the control bushing's return motion. The mechanics of the line of pipes, which are subjected to the pulsation of internal pressure in the borehole's complicated profile [which is true of the great majority of modern boreholes] is such that at the fastening point (the mine bottom anchor), axial and rotational stresses accumulate, which, upon weighing the anchor (of the hydraulic, in this case when circulation is interrupted), can lead to denting and damage to the control element, which is not in the operating position.
The objective of the invention is to reduce the risk of accidents in mechanically drilling through a stratum, and to expand the range of applications of the device for drilling through a stratum.
This object is attained by means of the features recited in claim 1.